Rock hounds are on the hunt for new carbon minerals

A new challenge has scientists searching for dozens of unknown, beguiling crystals

CAN YOU DIG IT? Abellaite, ewingite and leószilárdite (clockwise from left) are three of the seven carbon-bearing minerals recognized by the International Mineralogical Association in the past year. A search is on to find dozens more undiscovered carbon minerals.

Left: Matteo Chinellato; right: Travis Olds

Like many abandoned mines, the Eureka uranium mine in northern Spain is a maze of long, dank tunnels. Water seeping down the walls carries dissolved substances that percolated through rocks overhead. As the water evaporates into the tunnels’ cool air, some of those dissolved ingredients combine to make new substances in solid form.

“The mine is a crystallization factory of weird minerals,” says Jordi Ibáñez-Insa, a physicist at the Institute of Earth Sciences Jaume Almera in Barcelona.

Including the uranium-bearing ores that attracted miners to Eureka in the first place, scientists visiting the mine have cataloged 61 different minerals — solids that have a distinct chemical recipe and arrangement of atoms. The latest find, called abellaite, is a rarity that grows in small pincushions of tiny crystalline needles about 40 to 50 micrometers long. Discovered in July 2010, the mineral has been found only on the walls of a 3-meter-long stretch of one

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